A. Specific Aims Models of reading have long considered vocabulary knowledge an important source of variation in reading comprehension, particularly as it affects higher-level language processes such as grammatical processing and construction of schemata and text models (Adams &Collins, 1977;Chall, 1987;Proctor, Carlo, August, &Snow, 2005;see also the results of cross-project analyses cited in the Research Overview above). More recently, vocabulary has taken an even more central role in models of reading as research uncovers its influence on earlier reading and reading-related skills, including phonological, orthographic, and morphosyntactic processes (Anglin, 1993;Carlisle &Nomanbhoy 1993;Muter &Diethelm, 2001;Verhallen &Schoonen, 1993;Wang &Geva, 2003). It is well established that children who speak a language other than English at home lag behind their monolingual peers in vocabulary (Oiler, 2002) and that their rate of development is insufficient to close the gap. Fourth grade outcomes for children in the Subproject 2 sample of the current Program Project indicated that they were performing well below grade level in oral language proficiency, scoring at the high first grade level on the Woodcock Language Proficiency Battery (WLPB) Picture Vocabulary subtest. This is consistent with data from the National Center for Education Statistics (2003) that indicate fourth grade performance on the NAEP reading test shows a 22-29 point scale score advantage for children living in homes where a language other than English was never used compared with children who lived in homes where a language other than English was always used. To address these issues, the proposed project will focus on the vocabulary development of Englishlanguage learners (ELLs) in the early elementary grades. Our goals in Subproject 3 are to describe ELLs'vocabulary knowledge (Study 1), and use that information to design and evaluate a series of interventions to improve students'vocabulary knowledge (Studies 2 and 3) to determine which instructional strategies are most effective for teaching which kinds of words.